body {
    width:100%;
    margin: 0 auto;
    min-width: 320px;
    max-width: 640px;
    background: #fff;
    font-size: 14px;
    font-family: -apple-system, Helvetica, sans-serif;
    line-height: 1.5;
    color: #666;
    }
ul {
    margin:0;
    padding:0;
    list-style: none;
}
img {
    vertical-align: top;
}
a {
    color: #666;
    text-decoration: none;
}
.app {
    height: 45px;
}
.app ul li {
    float: left;
    height: 45px;
    background-color: #333333;
    text-align: center;
    line-height: 45px;
    color: #fff;
}
.app ul li:nth-child(1) {
    width: 8%;
}
.app ul li:nth-child(1) img {
    width: 20px;
    vertical-align: middle;
}
.app ul li:nth-child(2) {
    width: 10%;
}
.app ul li:nth-child(2) img {
    width: 30px;
    vertical-align: middle;
}
.app ul li:nth-child(3) {
    width: 57%;
}
.app ul li:nth-child(4) {
    width: 25%;
    background-color: #f63515;
}
/* 搜索 */
.search-wrap {
    position: fixed;
    width: 100%;
    overflow: hidden;
    min-width: 320px;
    max-width: 640px;

}
.search-btn {
    position:absolute;
    top: 0;
    left: 0;
    width: 40px;
    height: 44px;
}
.search-btn span {
    display:block;
    width: 20px;
    height: 18px;
    background: url(../images/line.png) no-repeat;
    background-size: 100% 100%;
    margin: 14px 0 0 15px;

}
.search-login {
    position:absolute;
    top: 0;
    right: 0;
    width: 40px;
    height: 44px;
}
.search-login span {
    display: inline-block;
    margin: 10px 0;
    color: #fff;
    font-size: 14px;
} 
.search {
    height: 30px;
    background-color: #fff;
    border-radius: 15px;
    margin:7px 50px;
    overflow: hidden;
}
.jd-icon {
    position: relative;
    float: left;
    display: block;
    width: 20px;
    height: 15px;
    background: url(../images/jd.png) no-repeat;
    background-size: 100% 100%;
    margin: 8px 8px 0 15px;
}
.jd-icon::after {
    position: absolute;
    top: 0;
    left: 26px;
    content: '';
    border-right: 1px solid #ddd;
    height: 16px;
}
.search-icon {
    position: relative;
    float: left;
    display: block;
    width: 18px;
    height: 15px;
    background: url(../images/jd-sprites.png) no-repeat -80px 0;
    background-size: 200px;
    margin: 8px 0 0 5px;
}
/* 主体部分 */
.slider img {
    width: 100%;
}
/* 品牌日 */
.brand {
    border-radius: 10px 10px 0 0;
    overflow: hidden;
}
.brand a div {
    float: left;
    width: 33.33%;   
}
.brand a div img {
    width: 100%;
}
/* 导航栏 */
nav {
    padding-top: 5px;
}
nav a {
    float: left;
    width: 20%;
    text-align: center;
}
nav img {
    width: 40px;
    margin: 10px 0;
}
nav span {
    display:block;
}
.news {
    margin-top: 180px;
}
.news a {
    float: left;
    width: 50%;
    box-sizing: border-box;
}
.news a:nth-child(n+2) {
    width: 25%; 
    border-left: 1px solid #ccc;   
}
.news a img {
    width:100%;
}